Mechanical connections for splicing or terminating electrical conductors, such as the common sleeve connector which is compressed or "crimped" onto the end of the conductor, have been the accepted standard of the electrical industry for many years. Such connections have the advantages of simplicity and economy and long use has proved their reliability on copper conductors.
The substitution of aluminum for copper conductors as carriers of electric current is now economically desirable. However, until now mechanical connections to aluminum conductors have been unreliable because aluminum has a greater tendency than copper to creep under continued stress and because a nonconductive oxide surface film rapidly forms on exposed aluminum. Thus, for example, crimped or coined connectors as described in U.S. Pat. No. 2,375,480 provide fully acceptable connections to copper conductors but have been found to produce unreliable connections to aluminum conductors.